when you can't be with the papa.... #freeslw #POOLPARTY #mymomsbodtho

A photo posted by tallulah (@buuski) on

Demi Moore poses in her swimming pool with her children in an Instagram photo posted by her daughter Tallulah

A 21-year-old man was found dead in Demi Moore's swimming pool, it has been reported.

The unnamed man was discovered in the pool of the actress's Los Angeles home at 5:30am local time on Sunday (19 July).

Law enforcement services told TMZ the man did not know how to swim and it appears that he slipped and fell in the pool and drowned.

When officers arrived at the home on the 9000 block of Oak Pass Road in the west of the city, a small crowd were gathered around the body.

There was reportedly a party at the house on Saturday night, but neither Moore, 52, nor her children were home at the time of the tragedy.

Police say the dead man was associated with someone who had access to the pool, but was not a relative. It is believed the man was invited to the house by an assistant to one of the women.

The source added that there was a 'limited amount' of alcohol at the party.

Celebrity news website TMZ quotes a neighbour as saying that Moore's children have been throwing regular pool parties at the house.

Moore has three children, Rumer Willis, 26, Scout LaRue Willis, 23, and Tallulah Belle Willis, 21, her daughters with the actor Bruce Willis.

Tallulah Willis' Instagram suggests she was in New York this weekend with Scout to celebrate her sister's 24th birthday, on Monday. (20 July)

Tallulah has recently shared several photos on her Instagram of late-night pool parties, including one that was captioned 'this picture doesn't do justice to the glory that was our pool party last night'.

Moore renovated the 1950s canyon-side house with former husband Ashton Kutcher.

A Los Angeles Police Department officer confirmed the West LA department was conducting an investigation into the man's death, Los Angeles Daily News reports.

Tallulah Willis posted this photo of a pool party to her Instagram page